The expression */ x + s * i. n
is often called a factorial function but,
to avoid confusion with the function ! ,
we will call it a stope; the factors occurring
in its definition differ by steps of size s,
like the steps in a mine stope. Stopes are useful in actuarial work and
in the difference calculus.

The stope is a variant of the power ^
(being equivalent for the case s=:0),
and is provided by the fit conjunction in the variant ^!.s.
For example:

The phrase +/c * x^!.s i.#c
is called a stope polynomial, just as +/c*x^i.#c
may be called a power polynomial. We define an
adverb P that applies to any step size s to provide
the corresponding stope polynomial:

As illustrated above, stope polynomials are (for a suitable
choice of coefficients) equivalent to ordinary polynomials.
Moreover, the transformations between them are provided by
a matrix product as follows: